The present invention relates to a method and apparatus for straightening the pins of a semiconductor or computer chip, integrated circuit or logic circuit. More particularly, the present invention relates to a method and apparatus by which the quality of large numbers of such pin grid arrays is quickly and conveniently improved.
Computer chips, logic circuits, microprocessor chips, integrated circuits, and other semiconductor devices generally include an array of nominally parallel metal pins extending from at least one side thereof. All such devices shall be referred to herein as pin grid arrays. Although there may be different numbers of pins on different types of pin grid arrays, and the pins may be of different lengths or arrangement, the pins are generally arrayed in rows and columns and project from the wafer of the pin grid array at a right angle with respect thereto.
Complex pin grid arrays, as well as those intended for critical operations, are often quite expensive such that quality control is an extremely important part of their production, and a frequent quality control problem is the bending or, in extreme cases, breaking, of those metal pins. The problem is an almost inevitable result of the handling of the pin grid array during production, packaging and shipping, and is particularly acute when the pins are constructed of highly conductive metals, such as gold. Especially when the pin grid array is to be assembled by robotic or other automatic manufacturing method, a pin grid array without parallel pins, i.e., pins which project from the wafer at a right angle, is likely to be considered a reject, especially when, so far as is known, there is no convenient, rapid and readily available method or apparatus available for straightening the bent pins. It is, therefore, an object of the present invention to provide such a method and apparatus.
Even when being incorporated into an electrically or electronically operated device for which final assembly is accomplished manually such that the pin grid array can be inspected visually or tested before assembly, any bent pins are generally straightened manually. Manual straightening of the pins is accomplished either with fingertips, which has the almost inevitable result of slightly bending some previously straight pins even though the one or more bent pins may be significantly straighter, or with a pair of small pliers or similar implement. In the latter case, the implement often scratches the pins, which is problematical when the pins are plated, e.g., gold plated on copper or other, less conductive, metal. In the case of pins which are solid gold, using such an implement can result in the breaking of a badly bent pin. Further, manual handling of the pin grid array also increases the opportunity for the array to be dropped or bumped against another object. The ceramic wafer of the array is itself quite fragile and particularly susceptible to the formation of microscopic cracks which affect the functioning of the circuitry therein. It is, therefore, another object of the present invention to provide an apparatus for straightening the pins of a pin grid array that does not damage the pins.
It is another object of the present invention to provide an apparatus for straightening the pins of a pin grid array which is capable of straightening the pins of arrays of different dimensions, number of pins, pin diameters, and pin lengths.
It is another object of the present invention to provide an apparatus and method for straightening the pins of a pin grid array which does not involve manual handling of the pin grid array.
Still another object of the present invention is to provide an apparatus and method by which a pin grid array can be received directly from a production line or other assembly process and, after having the pins straightened, loaded into a shipping tube or other container.
It is a further object of the present invention to reduce the number of defective pin grid arrays having defects as a result of the bending of the pins thereof.
These, and other objects, features and advantages of the present invention will be apparent to those skilled in the art from the following description of a presently preferred embodiment of an apparatus constructed in accordance therewith.